114914domain: NAppears in sequencesG.f.: 1 + Sum_{n>=1} a(n)*x^n/(1 - x^n) = Product_{n>=1} (1 + x^n)/(1 - x^n).at n=29A300274a(n) is the number of permutations that avoid 312 and 4321 and whose square avoids 321.at n=16A381859